Synthesis of zeolites by hydrothermal reaction of zeolite P1

New synthetic zeolites incorporating alkaline earth elements and routes for preparing those zeolites by hydrothermal alteration of zeolite P1 are disclosed. New methods for producing P1 zeolites are also identified. Synthetic heulandite, brewsterite, epistilbite and harmotome, among other zeolites can be prepared.

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Claims

1. A method of making a zeolite, comprising the steps of forming a mixture of a P1 zeolite in aqueous solution, said solution comprising at least one alkaline earth cation; and heating said mixture to produce a zeolite that is different from P1 but includes said alkaline earth cation.

2. A method according to claim 1, wherein said P1 zeolite has a silicon to aluminum ratio of greater than or equal to about 3.

3. A method according to claim 1, wherein said zeolite product is a member selected from the group consisting of heulandite, brewsterite, epistilbite, and harmotome.

4. A method according to claim 1, including the further step of adding seeds of a zeolite to said mixture.

5. A method according to claim 1, wherein said heating step is carried out at a temperature from about 100.degree. C. to about 300.degree. C.

6. A method according to claim 1, wherein said heating is carried out for a period of greater than about 1 day.

7. A method according to claim 1, wherein said alkaline earth cation is a member selected from the group consisting of calcium, strontium and barium.

8. A method according to claim 7, wherein said alkaline earth cation is calcium and said heating step is carried out at a temperature from about 200.degree. C. to about 280.degree. C. for a period from about 7 days to about 24 days.

9. A method according to claim 7, wherein said alkaline earth cation is strontium and said heating step is carried out at a temperature from about 200.degree. C. to 240.degree. C. for a period of greater than about 1 day.

10. A method according to claim 7, wherein said alkaline earth cation is barium and said heating step is carried out at a temperature of about 240.degree. C. for a period of greater than about 7 days.

11. A method according to claim 1, wherein said solution further comprises an alkali metal cation.

12. A method of making a zeolite having a heulandite topology, comprising the steps of forming an aqueous mixture of an alkaline earth cation and adding a P1 zeolite thereto; and heating said mixture for a period of time to produce said zeolite having a heulandite topology and a molar composition in terms of mole ratios expressed by the formula nXO:mY.sub.2 O:Al.sub.2 O.sub.3:6-8 SiO.sub.2:zH.sub.2 O, wherein X is at least one alkaline earth cation selected from the group consisting of Ca and Sr, Y is an alkali metal cation, 0<n.ltoreq.1, 0.ltoreq.m, n>m, n+m is approximately 1, and z.gtoreq.0.

13. A method according to claim 12, wherein X is Sr.

14. A method according to claim 12, wherein said mixture is heated to a temperature from about 100.degree. C. and about 300.degree. C.

15. A method according to claim 12, further comprising the step of adding seeds of a zeolite to said mixture.

16. A method according to claim 15, wherein X is Ca.

17. A method according to claim 12, wherein said P1 zeolite has a silicon to aluminum ratio of about 3 or greater.

18. A method according to claim 13, wherein said P1 zeolite has a silicon to aluminum ratio of about 3.3 or greater.

19. A method according to claim 13, wherein said mixture further comprises a hydroxide.

20. A method according to claim 13, wherein said period is greater than eight days.

21. A method according to claim 13, wherein the pH of said solution is alkaline and about 12 or less.

22. A method according to claim 13, comprising the further step of exchanging said P1 with an alkaline earth cation prior to said forming step.

23. A method of making a zeolite having a brewsterite topology, comprising the steps of:

forming an aqueous mixture of an alkaline earth cation, a P1 zeolite and seeds to form a mixture, wherein said seeds include a zeolite having a brewsterite topology; and heating said mixture for a period of time to produce said zeolite having a brewsterite topology and a molar composition expressed in terms of mole ratios by the formula nXO:mY.sub.2 O:Al.sub.2 O.sub.3:5.5-6.5 SiO.sub.2:zH.sub.2 O, wherein X is at least one alkaline earth cation selected from the group consisting of Sr and Ca, Y is an alkali metal cation, 0<n.ltoreq.1, 0.ltoreq.m, n>m, n+m is approximately 1, z.gtoreq.0 and wherein the amount of Ca.gtoreq.0 and the amount of Sr is greater than the amount of Ca.

24. A method according to claim 23, wherein said P1 zeolite has a silicon to aluminum ratio of at least 3 or greater.

25. A method according to claim 23, wherein said P1 zeolite has a silicon to aluminum ratio of at least 3.2 or greater.

26. A method according to claim 23, wherein X is Sr.

27. A method according to claim 23, wherein said mixture is heated to a temperature from about 200.degree. C. to about 240.degree. C.

28. A method according to claim 23, wherein the pH of said solution is alkaline and is about 12 or less.

29. A method according to claim 23, wherein said mixture further comprises a hydroxide.

30. A method according to claim 23, wherein said period is greater than about 1 day.

31. A method according to claim 23, comprising the further step of exchanging said P1 with an alkaline earth cation prior to said forming step.

32. A method of making a zeolite having a phillipsite topology, comprising the steps of forming an aqueous mixture of barium and a P1 zeolite; and heating said mixture for a period of time to form said zeolite having a phillipsite topology and a molar composition expressed in terms of mole ratios by the formula nXO:mY.sub.2 O:Al.sub.2 O.sub.3:4-6 SiO.sub.2:zH.sub.2 O, wherein X is at least one alkaline earth cation selected from the group consisting of Ba and Ca, Y is an alkali metal cation, 0<n.ltoreq.1, 0.ltoreq.m, n>m, n+m is approximately 1, z.gtoreq.0 and wherein Ca.gtoreq.0 and the amount of Ba is greater than the amount of Ca.

33. A method according to claim 32, wherein said P1 zeolite has a silicon to aluminum ratio of about 3 or greater.

34. A method according to claim 32, wherein said mixture is heated to a temperature from about 200.degree. C. to about 275.degree. C.

35. A method according to claim 32, wherein the pH of said solution is alkaline and about 12 or less.

36. A method according to claim 32, comprising the further step of exchanging said P1 with an alkaline earth cation prior to said forming step.

37. A method of making a zeolite having an epistilbite topology, comprising the steps of forming an aqueous mixture of a P1 zeolite, Ca.sup.2+ and an alkali metal cation; and heating said mixture for a period of time to form said zeolite and a molar composition expressed in terms of mole ratios by the formula nXO:mY.sub.2 O:Al.sub.2 O.sub.3:5-7 SiO.sub.2:zH.sub.2 O, wherein X is Ca, Y is an alkali metal cation, 0<n.ltoreq.1, 0.ltoreq.m, n>m and n+m is approximately 1 and z.gtoreq.0.

38. A method according to claim 37, wherein said P1 zeolite has a silicon to aluminum ratio of about 3 or greater.

39. A method according to claim 37, wherein said P1 zeolite has a silicon to aluminum ratio of about 3.2 or greater.

40. A method according to claim 37, further comprising the step of adding seeds of a zeolite to said mixture.

41. A method according to claim 37, wherein said mixture is heated to a temperature of from about 150.degree. C. to about 240.degree. C.

42. A method according to claim 37, comprising the further step of exchanging said P1 with an alkaline earth cation prior to said forming step.

43. A method of making P1 zeolite, comprising the steps of forming a sodium aluminosilicate gel from an aqueous mixture including silica and alumina at a basic pH; drying said gel to form a dried solid, said dried solid having a composition expressed by the formula in terms of molar ratios of 1-4 Na.sub.2 O:Al.sub.2 O.sub.3:9-10 SiO.sub.2; and mixing said dried solid with an aqueous solution of Na.sub.2 CO.sub.3 to form said P1 zeolite having a silicon to aluminum ratio of about 3 or greater.

44. A method according to claim 43, wherein said silica is a fumed silica.

45. A method according to claim 44, wherein said heating step is carried out at a temperature of from about 110.degree. C. to about 175.degree. C.

46. A method according to claim 43, wherein said silica is a colloidal silica.

47. A method according to claim 46, wherein said heating step is carried out at a temperature of about 150.degree. C.

48. A method for making P1 zeolite, comprising:

heating an aqueous mixture containing perlite and an alkali metal cation in a basic environment to form said P1 zeolite having a silicon to aluminum ratio of 3 or greater.

49. A method according to claim 48, wherein said P1 zeolite has a silicon to aluminum ratio of 3.2 or greater.

50. A method according to claim 48, wherein said heating step is carried out at a temperature of from about 110.degree. C. to about 240.degree. C.

51. A method according to claim 48, wherein said P1 zeolite is formed in a period of time from about 2 hours to about 11 days.

52. A method of making P1 zeolite, comprising the steps of forming an aqueous mixture of Al(OH).sub.3 and NaOH; adding colloidal silica to said aqueous mixture to form a gel precursor; stirring said gel precursor to form a gel; heating said gel at about 110.degree. C.-175.degree. C. to produce said P1 zeolite, wherein said gel precursor has a composition such that said P1 zeolite has a silicon to aluminum ratio of about 3 or greater.

53. A method according to claim 52, wherein said P1 zeolite has a silicon to aluminum ratio of about 3.2 or greater.

54. A method according to claim 52, wherein said P1 zeolite is heated at about 150.degree. C. for a period of time from about 2 days to about 7 days.

55. A method according to claim 53, wherein the pH of said mixture is about 12-13.

56. A method of making a zeolite, comprising the steps of: forming a mixture of a P1 zeolite in aqueous mixture, said mixture comprising at least one alkali metal cation; and heating said mixture to produce a zeolite that is different from P1 but includes said alkali metal cation.

57. A method according to claim 56, wherein said zeolite product is a member selected from the group consisting of analcime and mordenite.

Referenced Cited
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Other references
  • Barrer et al., "Hydrothermal Chemistry of Silicates. Part XIII, Synthetic Barium Aluminosilicates," J. Chem. Soc., 1964, pp. 2296-2305 No Month. Barrer, "Some Researches in Silicates: Mineral Synthesis and Metamorphoses," Trans. Brit. Ceramic Soc., vol. 56, pp. 155-184, 1957 No Month. Hakansson et al., "Structure of High-Silica Variety of Zeolite Na-P," Acta Cryst., C46, pp. 1363-1364, 1990. Meier et al., "Atlas of Zeolite Structure Types", 1992, pp. 66, 67, 90, 91, 100, 101, 106, 107, 110, 111, 164, 165, 189 & 194. (No Month).
Patent History
Patent number: 5935551
Type: Grant
Filed: Jul 29, 1997
Date of Patent: Aug 10, 1999
Assignee: California Institute of Technology (Pasadena, CA)
Inventors: Mark E. Davis (Pasadena, CA), Shervin Khodabandeh (Pasadena, CA)
Primary Examiner: Mark L. Bell
Assistant Examiner: David Sample
Law Firm: Limbach & Limbach LLP
Application Number: 8/836,966
Classifications
Current U.S. Class: Zeolite (423/700); Seed Used (423/709); Synthesized From Naturally Occurring Product (423/712); Mordenite; E.g., Na-d, Pttilolite, Zeolon (423/DIG25)
International Classification: C01B 3926; C01B 3928; C01B 3946;